Modularity, scalability and flexibility are now essential requirements for efficient and cost effective data centers. Modularity is the building block that allows rapid on-demand deployment of infrastructures. Modularity minimizes capital expenditure and, thus, maximizes return on investment (ROI). Scalability relates to modularity, but is the additional key that enables a design to scale past the barrier of a predetermined fixed number of modules. It is the glue that allows the different types of modules to coherently scale: specifically computing modules with floor/space modules, power modules, and cooling modules. Flexibility further refines modularity and scalability by allowing any type of hardware from any vendor, with various power and cooling requirements, to coexist within the same data center. It is most crucial in the context of serving multiple tenants that choose to collocate their specific computing systems in a shared data center.
Recent power density increases in computer packaging are amongst the greatest limiting factors of scalability and flexibility in data centers. Current best practices suggest to partition large computing rooms into low, medium, and high power density zones. In this way, a limited form of scalability and flexibility can be reached, negating the need to overprovision the whole computing room with the highest possible power density capability. Nevertheless, forcing these zones to be sized a priori is hardly modular. The problem lies with the conventional data center design where a huge computing room is surrounded by proportionally sized mechanical and electrical rooms. Such arrangements are difficult to scale, because large distances limit the ability to efficiently distribute low voltage power to computing machinery, and move enough air to keep this machinery cool. Air cooling at large scales especially becomes daunting, because air velocity needs to be kept at acceptable levels using air conduits of limited cross-sections. Too much air velocity brings turbulence that in turn produces pressure differentials and non-uniform air distribution and poor cooling efficiency. Moving water over large distances is both much easier and efficient. However, bringing water all the way to the computer racks (or even inside the racks) creates other challenges like leak detection and proofing.
Another popular trend is to use shipping containers to host preconfigured and preassembled computing hardware. Although this approach can be very modular and, to some extent, scalable, it is not so much flexible. The physical dimensions of a standard shipping container impose severe space constraints that usually limit the computer form factors that can be hosted while rendering hardware maintenance operations more difficult. Promoters of this approach are often hardware vendors of some sort, using the container model to push their own hardware as the backbone of data centers. Container based data centers are most practical when computing resources need to be mobile for some reason. In practice, however, even though rapid initial deployment is an obvious competitive advantage, rapid redeployment is a less frequent requirement because of the relative short lifespan of computers. Moreover, there is the additional issue of the low voltage power feeds usually required by these containers that have limited space for in-container power transformation. For large-scale configurations, this forces either to inefficiently carry low voltage energy over large distances, or to combine computing containers with power transformation containers.
Energy efficiency is also a very important requirement for modern data centers, both because of its financial and environmental impact. The two main sources of power losses in data centers lie in voltage transformation and regularization, on the one hand, and heat disposal, on the second hand. Best practices for efficient electrical systems are to minimize the number of voltage transformation stages and to transport energy at higher voltage. Also, it is important to correctly size the electrical infrastructure according to effective needs, as underutilized electrical systems are usually less efficient. As for efficient heat disposal, there are mostly air-side and water-side economizers to exploit favorable outside climate conditions to totally or partially circumvent the need for power hungry mechanical chillers. The holistic problem, however, is how to design cost-effective and energy efficient data centers that are also modular, scalable, and flexible.
Finally, when considering air-side economizers, there is the additional problem of air pollution in high-density urban environments or industrial areas, where air contaminants, most notably sulfur dioxide, may produce a long-term corrosive effect on some unprotected electronic components. This issue implies that outside air must either be very well filtered or passed through air-to-air heat exchangers, in order to avoid having large amounts of air contaminant in continuous contact with computing systems.
In view of the foregoing, there is a need for an improved compact footprint data center module that mitigates at least some shortcomings of prior data center modules, and for methodology to build large-scale cost-effective data center complexes with such modules that mitigates at least some shortcomings of prior data methods to build large-scale data center.